> We've just been given the go-ahead to add a 1.2 GB SCSI disk
> <Micropolis 1598-15 cyl 1692 alt 2 hd 15 sec 80> onto our 4/490.
>
> We'd like to enable sync scsi on this disk, but the SunOS 4.1.1
> manuals don't indicate whether this is possible on a 4/490.
>
> Is sync scsi possible on a 4/490 running 4.1.1, and if so, how do we
> go about enabling it?

I apologize for the late summary. Been busy, dontchaknow!

Here is the answer:

> From: doug@perry.berkeley.edu (Doug Neuhauser)
>
> Not with the Sun SCSI controller. It does NOT support sync scsi.
> To have synchronous SCSI support you would need a third party
> controller such as a Ciprico Rimfire SCSI controller.

and

> From: sundev!ronin!kevin@Sun.COM (Kevin Sheehan {Consulting Poster Child})
>
> It depends on the interface - as I remember, the 4/490 uses the
> si or se board for SCSI, neither of which do sync. The only
> interface that does sync at the moment is the esp, which is on
> the SPARCStations and 4/390.

So that's it, sun-managers. Sounds like we're out of luck, since we
have an si0 controller board in our 4/490s.

Here are some other responses that I received, which contain both
general and specific info about sync ssci that might come in handy for
some people:

> From: mark@maui.Qualcomm.COM (Mark Erikson)
>
> The OS will automatically probe the drive and negotiate sync SCSI and
> the appropriate speed. Disabling sync SCSI on the drive may mean that
> the drive will not initate the negotiation reguarding sync SCSI.